Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Extrasolar Planet News: Superplanet Or Brown Dwarf?

30.11.2004


New observations of an oddball planetary system 150 light-years from Earth may force astronomers to rethink the textbook definition of a planet and the accepted idea about how such a body forms. The observations suggest that either some planets are superheavy or that planets can form from disks of gas and dust that encircle not just a single star but two starlike objects.



Two years ago, when astronomers at the Geneva Observatory in Sauverny, Switzerland, reported their findings on the sunlike star HD 202206, nothing seemed out of the ordinary. The team announced that a body at least 17.4 times as heavy as Jupiter orbits the star. The unseen body resides at an average distance from the star of 0.82 times the Earth-sun distance.

The same team, led by Alexandre Correia of the University of Aveiro in Portugal, has now found evidence for a second unseen body orbiting HD 202206. This object is at least 2.4 times as heavy as Jupiter and resides at an average distance from the star of 2.55 times the Earth-sun distance, the researchers report (http://xxx.lanl.gov/abs/ astro-ph/0411512).


According to International Astronomical Union standards, the heavier body is a failed star known as a brown dwarf. By the union’s definition, brown dwarfs range from 13 to about 75 times the mass of Jupiter. That’s heavy enough to burn deuterium at their cores but too light to burn any other nuclear fuel, as bona fide stars do.

In contrast, the lighter object would be classified as a planet, as long as it weighs less than the 13-Jupiter-mass cutoff, as the scientists strongly suspect. In that case, it would have formed from gas and dust coalescing within a disk of material that surrounded the star in its youth. This would make it the first planet known to orbit a pair of objects— goes around the star five times, the outer body goes around exactly once. This particular synchrony has never before been observed in a planetary system. Synchrony keeps objects in an especially powerful gravitational embrace.

Synchrony can’t happen by chance, Correia says. The team suggests that the two bodies are birds of a feather, born in the same way and at the same time.

In that case, the heavier object orbiting HD 202206 wouldn’t be a brown dwarf after all, but the heaviest planet known. If so, the disk from which the two planets arose would have to have been two to four times as heavy as expected, Correia told Science News.

Moreover, if the heavier body is a superplanet, “we have to rethink our definition of what is a brown dwarf and what is a planet,” says Correia. Some objects massive enough to burn deuterium may be brown dwarfs, while others may be planets, he notes. “Somewhat odd systems like this . . . challenge our overall thinking about the formation of giant planets and brown dwarfs,” says Alan P. Boss of the Carnegie Institution of Washington (D.C.).

It’s possible that the heavier object is a brown dwarf but that theorists haven’t yet been clever enough to figure out why it’s in sync with the outer planet, cautions Adam S. Burrows of the University of Arizona in Tucson.

Published in the Nov. 27 issue of Science News, a weekly news magazine.

| newswise
Further information:
http://www.sciencenews.org

More articles from Physics and Astronomy:

nachricht On Mars, sands shift to a different drum
24.05.2019 | University of Arizona

nachricht New Boost for ToCoTronics
23.05.2019 | Julius-Maximilians-Universität Würzburg

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New studies increase confidence in NASA's measure of Earth's temperature

A new assessment of NASA's record of global temperatures revealed that the agency's estimate of Earth's long-term temperature rise in recent decades is accurate to within less than a tenth of a degree Fahrenheit, providing confidence that past and future research is correctly capturing rising surface temperatures.

The most complete assessment ever of statistical uncertainty within the GISS Surface Temperature Analysis (GISTEMP) data product shows that the annual values...

Im Focus: The geometry of an electron determined for the first time

Physicists at the University of Basel are able to show for the first time how a single electron looks in an artificial atom. A newly developed method enables them to show the probability of an electron being present in a space. This allows improved control of electron spins, which could serve as the smallest information unit in a future quantum computer. The experiments were published in Physical Review Letters and the related theory in Physical Review B.

The spin of an electron is a promising candidate for use as the smallest information unit (qubit) of a quantum computer. Controlling and switching this spin or...

Im Focus: Self-repairing batteries

UTokyo engineers develop a way to create high-capacity long-life batteries

Engineers at the University of Tokyo continually pioneer new ways to improve battery technology. Professor Atsuo Yamada and his team recently developed a...

Im Focus: Quantum Cloud Computing with Self-Check

With a quantum coprocessor in the cloud, physicists from Innsbruck, Austria, open the door to the simulation of previously unsolvable problems in chemistry, materials research or high-energy physics. The research groups led by Rainer Blatt and Peter Zoller report in the journal Nature how they simulated particle physics phenomena on 20 quantum bits and how the quantum simulator self-verified the result for the first time.

Many scientists are currently working on investigating how quantum advantage can be exploited on hardware already available today. Three years ago, physicists...

Im Focus: Accelerating quantum technologies with materials processing at the atomic scale

'Quantum technologies' utilise the unique phenomena of quantum superposition and entanglement to encode and process information, with potentially profound benefits to a wide range of information technologies from communications to sensing and computing.

However a major challenge in developing these technologies is that the quantum phenomena are very fragile, and only a handful of physical systems have been...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

SEMANTiCS 2019 brings together industry leaders and data scientists in Karlsruhe

29.04.2019 | Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

First dust conference in the Central Asian part of the earth’s dust belt

15.04.2019 | Event News

 
Latest News

On Mars, sands shift to a different drum

24.05.2019 | Physics and Astronomy

Piedmont Atlanta first in Georgia to offer new minimally invasive treatment for emphysema

24.05.2019 | Medical Engineering

Chemical juggling with three particles

24.05.2019 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>